History: Life In The New York City, 19th Century, United States

Sociologists and criminologists have not reached consensus on what explains the dramatic decrease in the city's crime rate. Some attribute the phenomenon to new tactics used by the New York City Police Department, including its use of CompStat and the broken windows theory. Others cite the end of the crack epidemic and demographic changes.
Organized crime has long been associated with New York City, beginning with the Forty Thieves and the Roach Guards in the Five Points in the 1820s. The 20th century saw a rise in the Mafia dominated by the Five Families and they still are the largest and most powerful criminal organization in the city. Gangs including the Black Spades also grew in the late 20th century. As early as 1850, New York City recorded more than 200 gang wars fought largely by youth gangs. The most prominent gangs in New York City today are the Bloods, Crips, Latin Kings, and MS-13.